1. Field of the Invention
The present invention relates to adrenomedullin which is a novel peptide having a hypotensive effect, and proadrenomedullin N-terminal 20 peptide (hereinafter referred to as the "proAM-N20") having a catecholamine secretion inhibitory effect and proadrenomedullin N-terminal 10-20 peptide (hereinafter referred to as the "proAM-N(10-20)") having a sodium channel inhibitory effect, both of the proadrenomedullin N-terminal peptides being part of a proprotein of adrenomedullin. More particularly, the present invention relates to adrenomedullin which can be purified from human phenochromocytoma (hereinafter referred to as "human PC"); structural genes of adrenomedullin, proAM-N20 and proAM-N(10-20); adrenomedullin and its proproteins encoded by the structural genes; expression vectors having the structural genes; transformants having the expression vectors; production methods for adrenomedullin, proAM-N20 and proAM-N(10-20) by using the transformants; an antibody against adrenomedullin or proAM-N20; an assay for quantifying adrenomedullin or proAM-N20 in a sample by using the antibody; and peptides useful in the preparation of the antibody and in the assay.
2. Description of the Related Art
Mammalian circulation is regulated by subtle mechanisms involving several neural and hormonal factors. Vasoactive peptides such as brain natriuretic polypeptide (BNP), atrial natriuretic polypeptide (ANP) and endothelin are known as important regulators in the cardiovascular system. It is assumed that BNP and ANP participate in blood pressure regulation and electrolyte metabolism regulation.
In order to clarify the intricacies of circulation, it is important that still unidentified vasoactive peptides be discovered. Especially, hypotensive peptides are desired which are useful in diagnosis and treatment of hypertensive hypercardia and cardiac failure.